What's causing this spotting on leaves?

Sick Plants & Problems
#1

So this has been ongoing for a couple weeks over on https://overgrow.com/t/learning-with-lucy since my 5 plants have been moved into my flower room.

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It’s happening on random leaves on all 5 of my plants.

It looks like spider mite damage to me but I have been checking leaves constantly for them and any other pests and am not seeing them. I have a 60-120x microscope I’ve plucked badly damaged leaves like the one above and put it under glass to examine it and saw no mites or eggs on the underside on topside of the leaves. I also took a white sheet of paper and jiggled the plants a bit over it and got nothing but specks of dirt and fibers and such.

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#2

My first guess would be thrips but you have a scope should be able to see them easily 2nd guess is bleaching I had something very similar in my leaves for a bit happen with me when I might of gotten water in the leaves while lights were on! How close is the canopy to the lights?

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#3

Is they any specks that have a tough time rubbing off? Like bug poo perhaps?

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#4

You could be having a small amount of condesation happening on the leaves when it’s dark. Water droplets act like a magnifying glass and could be burning little spots when the lights come on…

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#5

Canopy is 20 inches or so from the light. Some of this is on leaves in the midsection with little to no light exposure so this time I’m not so sure it’s bleaching.

As for specks/bug poo I do see stuff from time to time that looks like bug poo or little pieces of dirt. It’s on a basement floor so some dust does tend to blow around.

@Dewb THAT MIGHT BE IT! (sorry for caps but eureka moment)

My room (and location in general) is very (very) high humidity. RH is 61-65% and temp 26C with lights on and door open but when lights are off I have to close the door to prevent light leaks and it gets upwards of 90% RH and temp 20C sometimes during lights out.

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#6

I’v seen condensation on tightly over lapping leaves happens before lights come on in AM like @Dewb said I have grown in unusually dry conditions and still see this happen from time to time throw some light air on them or maybe pluck a few leaves!

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#7

They’ll need to be cleaned up this week anyway as we’re getting into week 3 of flower. I am putting another intake in asap to improve airflow, I have 2 oscillating fans going 24/7 I figured that would be enough to keep em dry and bug free but it is sooooo humid here right now.

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#8

looks like spider mites or maybe thrips… maybe put a piece of white paper on your soil and shake the plant around to see if anything falls off or leave it there to see if anything crawls on from the soil… check undersides of the leafs with a loupe… thrips are visible to the naked eye but very small and can be hard to find… check the stems too

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#9

I find thrips very hard to find with a scope. They are pretty fast moving, the adults look similar to fungus gnats, and they are very adept at hiding. Their damage is unmistakable though, IMO. It looks like hard water deposits on the leaves, but won’t rub off. This is a result of the larva rasping the leaves, then sucking the contents of the ruptured cells.

The damage I see looks like mite damage. Mites feed in a similar manner to thrips, but they pierce cells and suck out the contents. This gives the stippling look like you show.

Perhaps put out some sticky traps and see what you catch.

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#10

I haven’t seen a mite yet on these plants but I’ll be checking em over again this evening during lights on.

I already did the white paper trick and got nothing alive.

Not sure what the protocol would be at this point in flower on a 7-8 week strain.

I have a few things on hand here to spray mostly just fatty acid soaps and Pyrethrins. I already have fly traps hanging to detect FG I figure they’d pick up thrips too.

Just trying to be a bit proactive.

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#11

i’ve never had mites so i can’t really help knock on wood but i’ve sprayed method 1 pps up until a week before harvest before out of necessity (thrips) and the product was good… unfortunately it wasn’t the most effective against thrips (or i wasn’t treating effectively) but it’s designed for mites

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#12

I found a lot of leaves tonight with the speckling. It was a pruning night anyways so I pruned almost all affected leaves from all the plants. Went a little apeshit with the Diatomaceous Earth and hit the area in and around the pots pretty hard, as well as lightly dusting lower fan leaves.

I’m still quite certain this is a pest issue but I haven’t spotted anything directly yet.

@legalcanada I have actually had mites before (knock on wood) and long before I saw damage of this magnitude, I was able to spot the mites within a few minutes of searching. I’ve never had them to the point of making webs (knock on wood) because I usually catch them in early veg when I can go a little crazy with spraying. My plants are quite tall so I’m also able to get on my hands and knees and look up at them with the grow light shining through them and I see nothing. I’ve also not seen any eggs on the leaves I’ve chosen for exam under 60-120x magnfication.

My RH is always quite high too. During lights off with my door closed my RH gets upwards of 85% with temps of 19-20C. This may be slowing em down enough that its keeping their population so low it’s harder to spot them (good thing I guess). The damage however is getting annoying, my plants are definitely not looking happy before or after their pruning.

I’ve read some info on Method-1 before. As far as I can tell the active ingredients are rosemary and peppermint oils. I’ve used peppermint oil before in the past with a combination of other stuff and had success but I was sure the Peppermint Oil caused burning of the plant. If this were something I could just make with Rosemary and Peppermint I’d definitely try it. Spraying 1/3rd of the way through flower in a room with already high humidity might not be wise either.

Going to sleep and hopefully tomorrow will look better, Thanks for the tips everyone.

#13

I think you need to go nocturnal on these puntas! 3-4 hrs into the night cycle with perhaps a headlamp that has green light and see if that is when their most active by coming out of the hiding places !

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#14

That is a good idea for sure. I have a headlamp I can make green. Is the green to see better or to not cause issues with the plants?

I’m usually terrified of even cracking my door a little during lights off. Shining light directly on them during flower is also very scary. I won’t even shine a flashlight on them with the lights on lol. Think I might be over doing it?

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#15

Ya green lights don’t interfere with the lights off cycle with the plants they also make light bulbs as well that go for about 15$ from ones I’v seen and paid for either way your going to have to get the light close if using bulbs perhaps on and extension cord with socket adapter type thing!

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#16

yes i think it also has isopropyl alcohol listed in the nonactive ingredients

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#17

that looks like spider mites to me whats under the leaf

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#18

Can you see spider mites with the naked eye? I had something similar but could clearly see movement when I would concentrate on a fixed point on a leaf. It was slow like a caterpillar but just barely visible. I thought it was mites, and from what others saw (not the greatest photographer - used to be but that was many moons ago; had some great shots in the surfing mags) they thought so as well, but everyone kept saying I shouldn’t be able to see them clearly without a magnifier. I got some of that Mitey Mite and it seemed to do the job and it’s supposed to be natural/safe.

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#19

yes when it it gets really bad you can see them…if you can see them there are actually millions

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#20

90% RH during lights off sounds like mold problems in flower.

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